UK Firearms Licence Holders Drug Tested?

A recent news article describes how several people were subject to a drug test without prior warning at their home address by UK Police. This resulted in two of those people having their firearms seized on the spot. I discuss this and some of the concerns it brings up. If this testing was bought in as mandatory through the proper channels it may not be a bad thing but in its current format I found it could lead to some concerns to all Firearms and Shotgun licence holders.